Improvement in pistons or plungers for force-pumps



G. WQGILMORE. PISTON 0R PLUNGERFOR FORCE-PUMPS. N.171.,475.

Patented Dec. 28, 1875.

NV PETERS, PMOTO-IJTHDGRAPHER. WASHlNGTDN. D. c-

UNITED STATES VPATEET OFFICE.

GEORGE W.-GILMORE, OF WEBSTER, PENNSYLVANIA.

`IMPROVEMENT IN PISTONS R PLUNGERS FOR FORCE-PUMPS.

Specification forming part of Letters Patent N o. l7l,4715, datedDecember 28, 1875 application tiled April "es, 1875.

To all whom itmay concern.'

Be it known that I, GEORGE W. GILMORE, of Webster, Westmoreland county,State ot Pennsylvania, have invented an Improved Piston or Plunger'forForce-Pumps, of which the followingis a specification The object of myinvention is to cause the fluid to be discharged from the pump withgreater force and velocity than can be done with pistons of the ordinaryconstruction, and this to be done by theelasticity of a body of `air inthe piston acting on the column of water in the pump-barrel when thepiston is driven downward.

The invention consists in making the piston with a hollow' body, havingair-inlets at the top, and an opening' at the bottom, through which theair in the piston presses on the water in the barrel, when the piston isdriven downward. The air-inlets and the opening y in the bottom ofthepiston are alternately closed and opened by valves, which are operatedbythe recprocation of the piston, so that when the piston is lifted theair-inlets are opened, and the opening in the bottom is closed, and4water is prevented from enteringv the chamber 5 but when the piston isforced down the air-inlets are closed, and the opening in the bottom i-sopened, which permits the air in the chamber to press upon the fluid.

Figure l is a longitudinal section of my improved piston. Fig. 2 is anend View, showing the bottom of the piston; and Fig. 3 is also an endview, showing the top of the piston separate from it.

The following is a more particular description of said drawings whichare hereby made .a part of this speciication, letters ot' referencebeing the same in all the gures.

A is the piston, which is hollow, and forms the air-chamber F. b is theopening in the bottom of the piston, through which the air in thechamber E presses on the water in the barrel when the piston is drivendownward. a, a a a are theI air-inlets. G is a valve-rod guide, formedby .a small bar crossing the openingb, and having a hole in the centerg. H is also a guide-hole inthe top or head ot' vthe piston, Fig. 3. Dis the valve-rod, passing through the whole llength of the airchamber F,and retained in place by the guides G, g, and H. C and G are two valvesfast on the rod D, and at such points that when one is open the otherwill be closed. B is the piston-rod by which the piston is moved in thepump-barrel. The opening b is a hole in bottom ofthe piston aboutone-third less in diameter than. the air-chamber F, so as to form avalve-seat for the valve C, and the inlet is formed by several smallholes surrounding the guide-hole H.

When the piston Ais drawn up in the pumpbarrel, the valve C closes theopening b, and the inlets are uncovered, and the chamber F becomesvlledwith air. On the downward movement of the piston-valve G closes and Copens, and the air in the chamber E is caused to press on the top of thecolumn of water in the barrel, and its elasticity gives greater force tothe expulsion of the water from the pump than would be obtained by thepressure of the piston alone.

What I claim, and desire Letters Patent for, is-

A piston for force-pumps having4 the airchamber F, air-inlets t a,openings b, and provided with the valves C C', which alternately openand close the said openings by the reciprocation of the piston,substantially as and for the purpose hereinbetore described and setforth.

GEORGE w. GILMoEE.

Witnesses:

WM. M. GUTEEERT, JULIEN Moanow.

